Systematic Review Of The Role Of Footwear Constructions In .

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Journal of Sports Science and Medicine (2020) 19, 20-37 Review articleSystematic Review of the Role of Footwear Constructions in RunningBiomechanics: Implications for Running-Related Injury and PerformanceXiaole Sun 1, Wing-Kai Lam 2,3, Xini Zhang 1, Junqing Wang 1 and Weijie Fu 1, 4 1School of Kinesiology, Shanghai University of Sport, Shanghai, China; 2 Department of Kinesiology, Shenyang SportUniversity, Shenyang, China; 3 Li Ning Sports Science Research Center, Beijing, China; 4 Key Laboratory of Exerciseand Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, ChinaAbstractAlthough the role of shoe constructions on running injury andperformance has been widely investigated, systematic reviews onthe shoe construction effects on running biomechanics wererarely reported. Therefore, this review focuses on the relevant research studies examining the biomechanical effect of runningshoe constructions on reducing running-related injury and optimising performance. Searches of five databases and FootwearScience from January 1994 to September 2018 for related biomechanical studies which investigated running footwear constructions yielded a total of 1260 articles. After duplications were removed and exclusion criteria applied to the titles, abstracts andfull text, 63 studies remained and categorised into following constructions: (a) shoe lace, (b) midsole, (c) heel flare, (d) heel-toedrop, (e) minimalist shoes, (f) Masai Barefoot Technologies, (g)heel cup, (h) upper, and (i) bending stiffness. Some running shoeconstructions positively affect athletic performance-related andinjury-related variables: 1) increasing the stiffness of runningshoes at the optimal range can benefit performance-related variables; 2) softer midsoles can reduce impact forces and loadingrates; 3) thicker midsoles can provide better cushioning effectsand attenuate shock during impacts but may also decrease plantarsensations of a foot; 4) minimalist shoes can improve runningeconomy and increase the cross-sectional area and stiffness ofAchilles tendon but it would increase the metatarsophalangealand ankle joint loading compared to the conventional shoes.While shoe constructions can effectively influence running biomechanics, research on some constructions including shoe lace,heel flare, heel-toe drop, Masai Barefoot Technologies, heel cup,and upper requires further investigation before a viable scientificguideline can be made. Future research is also needed to developstandard testing protocols to determine the optimal stiffness,thickness, and heel–toe drop of running shoes to optimise performance-related variables and prevent running-related injuries.Key words: Running shoes; cushioning; bending stiffness; impact force; comfort perception.IntroductionOver the past 50 years, running shoes have experienced tremendous changes. That is, from very minimal to highlysupportive and cushioned shoes, and then to very minimaland finally back to highly cushioned shoes (Krabak et al.,2017). Shoes with various functionality were released because of technological advancements (e.g., structural andmaterial engineering) used in running shoe development,such as cushioned, stability and minimalist running shoes.Although cushioned midsoles can theoretically reduce theimpact forces by influencing the stiffness of one’s impactattenuation system and reducing the body’s deceleration(Shorten and Mientjes, 2011), the reported injury rate andperformance of running have not remarkably improvedover the years (Nigg, 2001). Therefore, reducing injuriesand improving performances by using running shoes havebecome a focus in both sport industries and academia.Running shoes are designated to improve shoe comfort, enhance running-related performance and reduce theinjury potentially. To identify the appropriate functionalityof running shoes, previous research has examined differentshoe constructions, which included shoelaces (Hong et al.,2011), midsole (TenBroek et al., 2014), heel flare (Stacoffet al., 2001), heel-toe drop (Malisoux et al., 2017), minimalist shoes (Fuller et al., 2015), Massai Barefoot Technology (MBT) ((Boyer and Andriacchi, 2009), heel cup (Liet al., 2018), shoe upper (Onodera et al., 2015), and bending stiffness (Stefanyshyn and Wannop, 2016). For one example, shoelace regulate the tightness of the shoe openingto allow a geometrical match between the foot and the shoebased on the individual’s preference. Good fit is considereda prerequisite for shoe comfort (Ameersing et al., 2003). Ashoelace system, heel counter or any other systems that cansecure the foot within the footbed should be integrated inrunning shoes.For another example, the midsole is an importantshoe component for cushioning and shock absorption ofrunning impacts. Midsole thickness is considered important to influence plantar sensations and alter foot strikepattern for shod and minimalist shoes running (Chambonet al., 2014). A wide range of heel-toe drops used in running shoes (e.g., 0 mm to 12 mm) has been shown to influence foot strike pattern and injury risk (Malisoux et al.,2016). Technically, minimalist shoe is defined as the footwear with high flexibility and low shoe mass, stack heightand heel-toe drop (Esculier et al., 2015). The minimalistshoe index is the combined scores of shoe quality, soleheight, heel-toe drop, motion control, and stabilisationtechniques, flexibility, longitudinal flexibility and torsionalflexibility (Esculier et al., 2015). Recently, forefoot bending stiffness has received more attention because it has thepotential to influence both running-related injury and performance (Stefanyshyn and Wannop, 2016). Softer andthicker running shoes (Sterzing et al., 2013; Teoh et al.,2013) were claimed that reduced impact in order to reduceimpact-related injuries. However, Theisen et al., (2014)found that there was no difference in running-related injurybetween softer and harder shoes. Such a relationshipReceived: 29 June 2019 / Accepted: 22 October 2019 / Published (online): 24 February 2020

21Sun et al.between biomechanics and injury not well established inthe literature.While different shoe constructions showed the remarkable changes in running biomechanical and performance-related variables, no consistent findings on runningbiomechanics can be found for most shoe constructions.For example, shoe cushioning properties are interplayedwith multiple footwear constructions including midsolehardness, midsole thickness, heel-toe drop, and crash-pad.The efficacy of isolated footwear constructions on runningperformance requires further investigation. Furthermore,analysing the development trend of running shoes can provide valuable guidelines to understand the roles of variousfootwear constructions in lower extremity biomechanics.Therefore, the current review aimed to examine the effectof different footwear constructions on running biomechanics and review the development status of running shoes related to injury, performance and applied research.MethodsSystematic review processFigure 1. Search and screening procedure.We followed the Preferred Reporting Items for SystematicReviews and Meta-Analyses (PRISMA) guidelines for thissystematic review (Alessandro et al., 2009). A standardisedelectronic literature search strategy was performed usingthe following keyword combinations: “running shoes” OR“running footwear” AND (“upper” OR “shoe lace” OR“midsole” OR “minimal shoes” OR “minimalist” OR “stiffness” OR “bending stiffness” OR “heel flare” OR “heelcup” OR “friction” OR “traction” OR “Masai BarefootTechnologies” OR “MBT”) AND PUBYEAR from 1994to September 2018 via the five databases (Elsevier, Ebsco,WoS, SAGE Knowledge e-book database, and PubMedCentral) and Footwear Science. WKL and WJF agreed onthe use of the search terms. Figure 1 summarises the searchand selection processes. All articles were input into Endnote to eliminate duplicates. Then, the original research articles in peer-reviewed journals that investigated the effectof shoe constructions on biomechanical changes duringrunning were included. The exclusion criteria included duplicates, orthotics, non-biomechanical related (i.e., onlyphysiological-, biochemical-, and medical-related), nonrunning shoe related, non-English or non-full text articles.

22Footwear constructions affect running biomechanicsThis systematic review included mainly laboratory-basedbiomechanical studies, a Physiotherapy Evidence Database(PEDro) scale (Macedo et al., 2010) was used to assess thequality of each included study. Studies with a PEDro scoreof less than 6 were deemed as low quality and were notincluded in the review. Two independent raters (authorsXLS and XNZ) performed each step of the search and thePEDro quality assessment. When the steps or the qualityscores differed between the raters, it would be discussedand consulted with the third rater (author WJF) to reach afinal consensus.The effects of different running shoe constructionson athletic performance-related and injuries variables wereshown in Tables 1 to 9, respectively. The injury-relatedvariables included cushioning, motion control, reducesprain, lower pronation, lower plantar pressure in the braking phase. Meanwhile, the performance-related variablesincluded energy consumption, running efficiency, kinematics, GRF, and plantar pressure in the propulsion phase(Wing et al., 2019).Table 1. Summary of the studies on shoelace effect (n 4).Tested Subject InfoShoerunning (Numbers,ReferenceConditionsSpeedSex, Age,(m/s) Landing type)Hong etal.,(2011)1. Laced runningshoes (LS);2. Elastic-coveredrunning shoes (ES)HagenandHennig,(2009)1. REG6 (6 eyeletsregular lacing)2. WEAK6 (6 eyeletsvery weak lacing)3. TIGHT6 (6 eyeletsvery tight lacing)4. EYE12 (eyelets1 and 2)5. EYE135(eyelets 1,3,5)6. ALL7 (all 7 eyelets)Hagen etal.,(2010)Hagen etal.,(2011)1. All 7 eyelet (ALL)2. 6 eyelets-tightlacing (TIGHT6)3. 6 eyelets-regularlacing (REG6)4. Skipping the 6theyelet (A57)1. All 7 eyelets (ALL)2. 6 eyelets-tightlacing (TIGHT6)3. 6 eyelets-regularlacing (REG6)4. Skipping the 6theyelet (A57), M, 20.3,rearfootstriker20, M, 32,rearfootstriker14, M, 24,rearfootstrikerResultsOverview of review dataThe full search yielded 1260 articles (Figure 1). After excluding the articles which were duplicates, irrelevant andlow PEDro scores (i.e., less than 6), a total of 63 articleswere included into subsequent analysis.Effects of shoelaceFour included articles (Table 1) investigated the effects ofshoelace on running biomechanics. Three articles compared the effect of different shoelace patterns (6 eyeletsregular lacing, 6 eyelets-tight lacing, all 7 eyelets) on thebiomechanics during overground running (Hagen andFeiler, 2011; Hagen and Hennig, 2009; Hagen et al., 2010).One article investigated different running mechanics between laced and elastic-covered running shoes (Hong et al.,2011). As shown in Table 1, 6 eyelets-regular lacing wasthe most unstable than other patterns, and showed higherloading rate and heel peak pressure than all 7 relatedLS perceived forefootcushioning, heel cupfitting, shoe heel width,shoe forefoot width &shoe length;TreadmillLS max. rearfootrunningpronation;ES PP on 3rd, 4th &5th MTH; PP on other foot regions; contact area for allregions.Low lacing vGRF impact, PP on 3rdOverground& 5th MTH thanrunninghigh lacing; maximum pronation.TIGHT6, ALL &A57 perceived stabilitythan REG6;OvergroundA57, REG6 comfortrunningthan other; TIGHT6 is themost uncomfortable.InjuryrelatedNA6EYE12 the peakvertical forces than REG6and TIGHT6; TIGH 6,ALL7 and REGULA 6 loading rate & pronationvelocities than EYE12,EYE135, and WEAK6;High lacing heel &lateral midfoot PP thantighter lacing;REG 6 loading rate &heel PP than ALL7.6TIGHT6 PP on medialfoot dorsum than other;ALL, A57 PP ontarsal bones.6NA6High level (21,Low level:M, NA,A57 perceived stabilitySelfrearfoot striker); Overground & comfort than REG6;selectedLow levelrunningHigh level:Speed(20, M, NA,A57 perceivedrearfoot striker)comfort than other.Max maximum, PP peak pressure, vGRF vertical ground reaction force, MTH metatarsal head, NA Not available

23Sun et al.patterns (Hagen and Hennig, 2009; Hagen et al., 2010). Additionally, 6 eyelets-tight lacing was considered as the mostuncomfortable (Hagen et al., 2010).Effects of shoe midsoleNineteen included articles investigated the hardness (n 13), thickness (n 2), and material properties (n 4) of themidsoles, which would influence lower extremity biomechanics that is related to injury or athletic performance (Table 2). The PEDro score was “8” for only one, all of theother articles were equal to “6. 4”. Out of 13 studies (Stefanyshyn and Nigg, 2000; Willwacher et al., 2014; Macleanet al., 2009; Hardin et al., 2004) demonstrated that the increase in the stiffness/hardness of midsoles from AskerC40 to Asker C70 would be related to running performanceas indicated by the reduced energy lost at metatarsophalangeal and maximum rearfoot eversion velocity, andTable 2. Summary of the studies on midsole effect (n 19).Tested Subject InfoShoerunning (Numbers,ReferenceConditionsSpeedSex, Age,(m/s) Landing type)Baltich etal. (2015)Chambonet al.(2014)Dixon etal.,(2015)Hardin &Hamill,(2002)Hardin etal.,(2004)1. Asker C40 (Soft)2. Asker C52 (Medium)3. Asker C65 (Hard)increased positive work at metatarsophalangeal and peakankle dorsiflexion velocity in running. However, 4 out of13 studies (Hardin and Hamill, 2002; Nigg and GerinLajoie, 2011; Teoh et al., 2013; Wakeling et al., 2002)showed no significant effects on peak tibial acceleration,running velocity, stride duration and all frequency spectralor time domain parameters of gastrocnemius medialis, biceps femoris and vastus medialis variables. Among the related studies, two included studies (Sterzing et al., 2013;Teoh et al., 2013) demonstrated soft midsoles could reduceimpact forces and loading rates, thereby minimising therisk of impact-related injuries.Two out of 19 articles found that thicker midsolescan provide better cushioning effects and attenuate shockduring impacts but may also decrease plantar sensations ofa foot (Robbins and Gouw, 1991).OutcomeTestingProtocol93, M 47, F 46,rearfoot striker30-m3.33 Group1:16-20yr over0.15 Group2:21-35yr groundGroup3:36-60yr runningGroup4:61-75 yr1. Barefoot (BF)2. 0-mm midsole (MT0)3. 2-mm midsole (MT2)3.34. 4-mm midsole (MT4)5. 8-mm midsole (MT8)6. 16-mm midsole (MT16)1. A neutral shoe withan average hardness of 52Asker C (CON);2. Medially-52 Asker C3lateral -60 Asker C (LAT1);3. Medially-52 Asker Clateral -70 Asker C (LAT2);1. Shore A40 (Soft)2. Shore A55 midsole(Medium)3.43. Shore A70 midsole(Hard)1. Shore A40 midsole(Soft)3.42. Shore A70 midsole(Hard)15, M, 23.9,rearfoot striker10, F, 50years,NA24, M, NA,rearfoot downhillrunning12, M, NA,Treadmillrearfoot striker runningPerformancerelatedSoft ankle stiffness thanMedium & Hard;FemaleSoft knee stiffness thanMedium&Hard;MaleSoft knee stiffness thanMediumBF & MT0 stance-phaseduration than MT16;BF initial plantarflexionthan shoe condition;BF strike index thanshoe condition;BF ankle dorsiflexion but knee flexionduring stance;BF max knee joint moments than MT0 & MT4; hip & knee flexionangles at TD.LAT1 adductionmovement than CONInjuryrelatedPEDroScoreSoft vGRF impactpeak than Medium& Hard6 peak GRF impact,peak tibialacceleration.6LAT2 max 1st loadingrate & eversionmovement than CON; peak knee abductormoment and peakrearfoot eversion.6 peak tibialacceleration.NA6Hard midsole peakankle dorsiflexionvelocity.NA6Yr year, vGRF vertical ground reaction force, MF midfoot, RF rearfoot, FF forefoot, Max maximum, MTP metatarsophalangeal, VO2 oxygenconsumption, EMG electromyography, RMS root mean square, RoM range of motion, NA Not available, TD Touch down.

24Footwear constructions affect running biomechanicsTable 2. Continued ReferenceLaw et al.(2018)Maclean,Davis, &Hamill,(2009)Nigg etal., (2011)ShoeConditions1.1-mm midsolethickness (MT1)2.5-mm midsolethickness (MT5)3.9-mm midsolethickness (MT9)4.21-mm midsolethickness (MT21)5.25-mm midsolethickness (MT25)29-mm midsolethickness (MT29);1.Asker C70midsole (Hard)2.Asker C55midsole (Medium)3.Asker C40 (Soft)1.Asker C40 (Soft)2.Asker C52 (Medium)3.Asker C65 (Hard)7 dual-density shoecondition:Medial dual density midsoleelements with 62 Asker COriwol1. M1 is the neutral al.,2. M2 – 36 mm(2011)3. M3 – 52 mm4. M4 – 58 mm5. M5 – 79 mm6. M6 – 89 mm7. M7 – 104 mmAll shoe with AskerC50 MFSterzing1.Soft-RF/Soft-FF (SS)et al.,2.Medium-RF/Medium(2013)FF (MM)3.Hard-RF/Hard-FF (HH)4.Soft-RF/Hard-FF (SH)5.Hard-RF/Soft-FF (HS)Sterzinget al.(2015)Tested Subject Inforunning (Numbers,SpeedSex, Age,(m/s) Landing type)OutcomeTestingProtocol15, M, 31.4,SelfTreadmillrearfoot uryrelatedThinner midsole (MT1& MT5) contact timethan MT25 & MT29; footstrike angle,cadence & stride length.Thinner midsole (MT1& MT5) verticalloading rates than(MT25 & MT29).612, F, 19-35,Rearfootstriker with iliotibial band orpatellofemoralpain syndromeOvergroundrunningHard shoe Maxrearfoot eversionvelocity.NA63.33 0.1754, M 36,F 18, 33.9,rearfoot striker30-movergroundrunning all frequency spectralor time domain parametersof gastrocnemius medialis, biceps femoris andvastus medialis.NA63.5 0.116, M, 29.4,rearfootstrikerOvergroundrunning all rearfootmotion variables.NA64.0 5%3.3 0.11. Soft medial/HardLateral (SMH)2.Medium medial/Medium lateral (MMM)3.33.Hard medial/Soft 10%lateral (HMS)4.Very Hard medial/VerySoft lateral (VHMVS)28, M, 23.8,rearfootstriker24, M, drunningSofter maxplantarflexion & pronation velocity thanstiffer shoes;MM sagittal footstrikeangle than SH & HS; Contact timeSH, SS, & MM max 1stloading rate than HH, HS;SH max 2nd loadingrate than MM, HH & HS;SS max 2nd loadingrate than HH & HS;MM max 2nd loadingrate than HH.SMH perceived softer atVHMVS PP atmedial midsolemedial region thanthan HMS;SMH & MMM;MMM perceived softer at VHMVS force-timemedial midsole than HMSintegral at rearfoot& VHMVS;than HMS & SMH;SMH ground contact time VHMVSC force-timethan HMS & VHMVS; integral at medical regionSMH max 1st loadingthan all other shoes;rate MMM & VHMVS;SMH force-timeVHMVS maximumintegral at centre thaninversion at touchdown than MMM & VHMVS;all other shoe condition;SMH force-time Cushioning, stability & integral at lateral regionpropulsion during push-offthan all other shoes66Yr year, vGRF vertical ground reaction force, MF midfoot, RF rearfoot, FF forefoot, Max maximum, MTP metatarsophalangeal, VO2 oxygenconsumption, EMG electromyography, RMS root mean square, RoM range of motion, NA Not available, TD Touch down.

25Sun et al.Table 2. Continued ShoeConditionsReferenceStefanyshynet al.,(2000)Teohet al.,(2013)Theisenet al.,(2014)Wang etal. (2012)Wunschet al.,(2016)Wunschet al.,(2017)OutcomeTestingProtocol1.Control shoe2. Stiff midsole5, M, 32,Over4.0 shoe (Stiff)rearfootground0.43.Very stiff midsolestrikerrunningshoe (Very stiff)1. medial stiffness 1C,Overlateral stiffnessselfM 16, F 14,ground1.6C (VSS)selected22.6,running2. same medial & lateral speedsstiffness 1C (CS )1.Soft midsole247, M 136,Overshoe (Soft)2.61F 111, 41.8,ground2.Hard midsole2.69leisure-timerunningshoe (Hard)distance runners1.Control (Control)Willwacher2.Medium stiffnesset al.(Medium)(2014)3.High stiffness (High)Wakeling,& Nigg,(2002)Tested Subject Inforunning (Numbers,SpeedSex, Age,(m/s) Landing type)1.Shore C61midsole (Hard)2.Shore C41midsole (Soft)1.Ethylene VinylAcetate (EVA)2.Polyurethane -1 (PU1)3.Polyurethane -2 (PU2)1.Leaf spring-structuredmidsole (Leaf)2.Standard foam (Foam)1.Leaf spring-structuredmidsole (Leaf)2.Standard foam (Foam)PerformancerelatedInjuryrelatedStiff energy lost at MTP; energy generation & absorption at ankle, knee & hip;NA energy stored &reused at MTP.VSS the peak EKAMthan CS; runningVSS the maximumspeedmedial GRF than CS in anterior GRF than CS.NA running-related injury. Injury location, type,severity or category.Medium & High overallStance time & push-off time than19, M, 25.3,3.5Control; High Negative work & rearfoot 5%positive work at MTP than Controlstriker& Medium. Effective contacttime & braking time. EMG intensities variedOver3, M, 26, NAin different shoe condition;2.5-4.2ground3, F, 23.3, NA running velocity, striderunningdurationEVA & PU-1 peak forcesthan PU2 at all runningOver15, M, 21.2,distance;groundNA rearfoot strikerPU-1 peak forces at 200-30outdoorkm than 0 km;runningEVA energy returnperformance than PU1&PU22 mmol/l10, M, 33.1,Leaf stride length but Overbloodlong-distancestride rate & oxygen congroundlactaterearfootsumption than foam;runningspeedstriker strike patternLEAF energy absorption athip joint as well as energy9, M, 32.9,3.0 Indoorgeneration at ankle joint;long-distance0.2trackLEAF muscle forces of therearfoot strikersoleus, gastrocnemius lateralis& gastrocnemius NA6NA6Yr year, vGRF vertical ground reaction force, MF midfoot, RF rearfoot, FF forefoot, Max maximum, MTP metatarsophalangeal, VO2 oxygenconsumption, EMG electromyography, RMS root mean square, RoM range of motion, NA Not available, TD Touch down.Effects of heel flareOnly one included article (Table 3, Figure 2) investigatedthe effects of heel flare construction (lateral heel flare of25 , no lateral heel flare 0 , rounded heel) on running bioTable 3. Summary of the studies on heel flare effect (n 1.)Tested Subject InfoShoerunning (Numbers,ReferenceConditionsSpeedSex, Age,(m/s) Landing type)1. Lateral heel flare of25 (Flared)Stacoff et5, M, 28.6,2. No lateral heel flareal., (2001)2.5–3rearfoot0 (Straight)striker3. Rounded heel(Round).NA Not availablemechanics. However, there were no significant differencesin tibiocalcaneal and ankle kinematics (initial inversion,maximal eversion velocity) among heel flare conditions(Stacoff et al., rmancerelated Tibiocalcaneal rotations &shoe eversion; Initial inversion, maxeversion velocity, max &total eversion on bone, &total internal tibial rotation.InjuryrelatedNAPEDroScore6

26Footwear constructions affect running biomechanicsFigure 2. Three different heel flares.Effects of heel–toe dropSeven included articles (Table 4) investigated the effects ofheel-toe drop on running. The PEDro scores of 5 articleswere 6 and the other two were 7. As shown in Table 4, allTable 4. Summary of the studies on heel-toe drop effect (n 7).TestedSubject x, Age,(m/s)Landing type)Besson etal., (2017)Chambon etal. (2015)1. Heel–toe drop10 mm (D10)2. Heel–toe drop6 mm (D6)3. Heel–toe drop0 mm (D0)1. Heel–toe drop0 mm (D0)2. Heel–toe drop4 mm (D4)3. Heel–toe drop8 mm (D8)4. Barefoot (BF)1. Heel–toe drop10 mm (D10)Malisoux et2. Heel–toe dropal., (2017)6 mm (D6)3. Heel–toe drop0 mm (D0)1. Heel–toe drop 10mm (D10)Malisoux et2. Heel–toe drop 6al. (2016)mm (D6)3. Heel–toe drop 0mm 14, F, 21.4,rearfootstrikerthese studies investigated different performance-relatedvariables. Shoes with higher drops were found to be relatedto increase knee adduction (Malisoux et al., 2016), kneeexcursion, knee flexion at midstance, stance time(TenBroek et al., 2014) and reduce tibial acceleration, initial ankle plantarflexion, initial knee extension angle(TenBroek et al., 2014). For running mechanics, shoes withhigher drops would increase net knee flexion moment inthe push-off, but reduced net joint ankle flexion momentduring braking phase (Besson et al., 2017). In a randomizedcontrolled study (Malisoux et al., 2016), cox proportionalhazards regression was used to compute the hazard rates inthe exposure groups, using first-time injury as the primaryoutcome and concluded that there was no significant difference of overall injury risk among different atedInjuryrelatedD0 Foot ground angle, ankledorsiflexion at initial & last 40%stance phase than D6 & D10;D0 AP GRF during first part ofstance phase than D6 & D10;D0 push-off time but Overground braking time than D6 & D10;runningD0 net joint ankle flexionmoment during braking phase net knee flexion moment in thepush-off phase compared toD6 & D10; knee & hip angles,& stance phase duration.12, M, 21.8, Treadmill &rearfootovergroundstrikerrunningOverground:D0 foot ground angle attouchdown than D8;BF loading rate than D8;Treadmill:BF & D0 foot groundangles than D8;BF & D0 ankle flexionduring stance phase than D8;BF knee flexion RoMthan D4 & D8;BF peak & loading rateof vGRF than D8; initial ankle angleNAD6 & D10 knee adduction59, M 42,than D0;TreadmillF 17, rearfoot contact time, flight time,runningstrikerstride frequency, stride length,hip vertical displacement553, M&F,D10 176; D6 190; OutdoorD0 187; 38;overgroundrearfoot striker (ocrunningcasional & regular)NANANAD6 & D0 injury riskin occasional runnersbut injury risk in regular runners; overall injury riskfor all participantPEDroScore6677Max maximum, RoM range of motion, GRF ground reaction force, AP anterior-posterior direction, ML medio-lateral direction, CoP centre ofpressure, NA Not available.

27Sun et al.Table 4. Continued ect Info(Numbers,Sex, Age,Landing type)Mits et al.(2015)1. Heel–toe drop 12mm (D12)2. Heel–toe drop 8mm (D8)3. Heel–toe drop 4mm (D4)4. Heel–toe drop 0mm (D0)0.97 10%14, M, 3 mm offsetTenBroek(Thin)et al. (2014)2.9–14 mm offset(Medium)3.12–24 mm offset(Thick)3.0Forefoot–rearfootoffset:1. 3–3 mm offset(Thin)2. 9–14 mm offset(Medium)3. 12–24 mm offset(Thick)4. Barefoot (BF)3.0TenBroeket al.,(2012)OutcomeTestingProtocolInjuryrelatedD8, & D12 max AP CoPOvergroundexcursion than D4;runningD8 range of AP CoP than D0; ML CoP variables.10, M, 18-55,rearfoot striker10, M, nningTreadmillrunningNAThin & Medium initial ankleplantarflexion than other;Thin initial knee extensionangle than other;Thick knee flexion atmidstance than Medium;Thick knee excursion thanThin & Medium;Thick stance time thanThin & Medium.Barefoot & Thin initialdorsiflexion than Medium & Thick;BF & Thin leg segment verticalat TD than Thick;Medium & Thick knee flexionexcursion than Thin & BF;Thin knee excursion than BF;Thin eversion excursion thanall other conditions;Thin stance time thanMedium & ThickBarefoot & Thin peak tibialacceleration than other condition;Medium peak tibialacceleration than ThickPEDroScore6NA6NA6Max maximum, RoM range of motion, GRF ground reaction force, AP anterior-posterior direction, ML medio-lateral direction, CoP centreof pressure, NA Not available.Effects of minimalist shoeTwenty included articles (Table 5) investigated the effectsof minimalist shoe on running. The PEDro scores of 18 articles were 6 and the other two were 7. Three included studies showed that minimalist shoes would improve runningeconomy (Fuller et al., 2017b; Michael et al., 2014; Warneet al., 2014) and other three included studies indicated thatminimalist shoes would increase the cross-sectional area,stiffness and impulse of Achilles tendon compared with theconventional shoes (Histen et al., 2017; Joseph et al., 2017;Sinclair and Sant, 2016). Furthermore, participants wearing minimalist shoes promote midfoot and/or forefoot running, with smaller footstrike angles (Fuller et al., 2016;Moore et al., 2014), more anteriorly shift of center of pressure (Bergstra et al., 2015), greater metatarsophalangealand ankle loading but smaller knee loading (Firminger andEdwards, 2016), compared to conventional shoes.Table 5. Summary of the studies on minimalist shoe effect (n 20).TestedSubject SpeedSex, Age,Protocol(m/s)Landing type)Bergstra1. Minimalist shoe (MS)et al.,MS 3.38; 18, F, AGE, Overground2. Standard running shoes(2015)SS 3.41 rearfoot striker running(SS)OutcomePerformancerelatedMS stance timethan Control; shoe comfort &landing strategyInjuryrelatedMS peak & mean pressurein medial, central & lateralforefoot during the entirecontact phase than SSPEDroScore6AT Achilles tendons, MVIC maximal voluntary isometric contraction, VE pulmonary ventilation, EMG electromyography, VO2 oxygen consumption,RoM range of motion, MTP metatarsophalangeal, NA not available.

28Footwear constructions affect running biomechanicsTable 5. Continued ReferenceBonacciet al.,(2013)Campitelliet al.,(2016)Firminger&Edwards,(2016)Frederickset al.,(2015)Fuller etal., (2017)Fuller eta., (2016)Goss etal., (2013)ShoeConditionsTestedrunningSpeed(m/s)Subject Info(Numbers,TestingSex, Age,ProtocolLanding oreBF knee flexion duringmidstance, peak internal1. Barefoot (BF);knee extension, knee abduction2. Minimalist shoe (MS);22,Overground moments negative work done,3. Racing flat shoe4.48 5% M 8, F 14,running& initial dorsiflexion thanNA6(Race);29.2, highlyshod condition;4. Athlete’s regular shoetrained runnersBF peak ankle power(RS)generation & positive workdone than MS & Race1. Vibram minimalist25-M; 16-F;MS thickness of24-weekshoe (MS)20-33,abductor hallucis muscle;NAtrainingNA72. Conventional shoerearfoot thickness of abductorprogramme(CS)strikerhallucis muscle.MS MTP eccentric work but MTP concentric work;MS peak plantarflexionmoment, angular impulse,cumulative impulse &MS MTP &eccentric work;15, M, 26

Over the past 50 years, running shoes have experienced tre-mendous changes. That is, from very minimal to highly supportive and cushioned shoes, and then to very minimal and finally back to highly cushioned shoes (Krabak et al., 2017). Shoes with various functionality were released be-